Rotation mechanism and robot using the same

ABSTRACT

A rotation mechanism includes a flange, a shaft, a first swing member, and a second swing member. The shaft extends along a first axis. The first swing member is rotatably connected to and received in the flange around a second axis substantially perpendicular to the first axis. The second swing member is rotatably connected to and received in the first swing member around a third axis substantially perpendicular to the first axis and the second axis. The shaft extends through the flange, the first swing member, and the second swing member. The shaft is non-rotatably and slidably received in the second swing member. A robot using the rotation mechanism is also provided.

BACKGROUND

1. Technical Field

The present disclosure generally relates to rotation mechanisms, andparticularly, to a rotation mechanism capable of swinging and a robotapplying the rotation mechanism.

2. Description of Related Art

Parallel robots have advantages of stability, load-bearing, favorableweight to load ratio, dynamic characteristics, and others. As parallelrobots and series robots cooperate, they may be used in many fields.Delta robots are typically parallel robots with three degrees offreedom, with simpler, more compact structure and favorable dynamiccharacteristics.

A typical delta robot includes a base, a movable platform, a shaft andthree control arms. The shaft and the control arms connect the movableplatform and the base. Opposite ends of the shaft are ball-pivoted onthe base and the movable platform, respectively. Opposite ends of eachcontrol arm are pivoted to the base and movable platform. During use, anelectric motor drives the arms and thus, the shaft, to move. As such,the movable platform moves in three dimensional space. However, movementrange of the control arms and the movable platform are limited by alength of the shaft.

Therefore, a rotation mechanism and a robot applying the same aredesired to overcome the described limitations.

BRIEF DESCRIPTION OF THE DRAWINGS

The components in the drawings are not necessarily drawn to scale, theemphasis instead being placed upon clearly illustrating the principlesof the present disclosure. Moreover, in the drawings, like referencenumerals designate corresponding parts throughout several views.

FIG. 1 is a schematic view of a robot of an embodiment of thedisclosure, the robot including a rotation mechanism.

FIG. 2 is an assembled, isometric view of a rotation mechanism,applicable in a robot, such as, for example, that of FIG. 1.

FIG. 3 is an exploded, isometric view of the rotation mechanism of FIG.1.

FIG. 4 is a cross-section of the rotation mechanism taken along lineIV-IV of FIG. 2.

FIG. 5 is a cross-section of the rotation mechanism taken along line V-Vof FIG. 2.

DETAILED DESCRIPTION

Referring to FIG. 1, an embodiment of a robot 200 is shown. The robot200 is a parallel robot with four degrees of freedom. The robot 200includes a base 201, a movable platform 203, three control arms 205rotatably connecting the base 201 with the movable platform 203, and arotation mechanism 100. The base 201 further includes a first actuator207 and a gear 202. The first actuator 207 and the gear 202 are mountedon the base 201. The gear 202 can be driven by the first actuator 207.In the illustrated embodiment, the first actuator 207 is a servo motor.

The rotation mechanism 100 includes a flange 10 fixed to the gear 202and a shaft 90 extending through the flange 10; and the rotationmechanism 100 has one end movably connected to the movable platform 203.The robot 200 further comprises three second actuators 209 connected tothe control arms 205, respectively, to drive the control arms 205.During operation, the second actuators 209 drive the control arms 205 tomake swinging maneuvers, thus providing movement to the movable platform203 on X, Y, Z axes. It can be understood that the movable platform 203may only move in one, two, or all three of the described axes.

Referring to FIG. 2 and FIG. 3, the rotation mechanism 100 furtherincludes a first swing member 20, two first pivots 30, a second swingmember 50, and two second pivots 60.

The flange 10 is annular and includes a first receiving hole 11 forreceiving the first swing member 20. The flange 10 defines two circularfirst shaft holes 13 in a sidewall thereof, and the first shaft holes 13are aligned with the same axis, such as the Y axis in the illustratedembodiment. The first shaft holes 13 are for receiving the first pivots30 and are communicated with the first receiving hole 11. The flange 10further defines a plurality of uniformly distributed mounting holes 15and two locking holes 17 in the top of the flange 10. Each locking hole17 communicates with one corresponding first shaft hole 13 and has anaxis substantially perpendicular to the first shaft hole 13. Themounting holes 15 are configured to fix the flange 10 to the gear 202.

The first swing member 20 is substantially annular. The first swingmember 20 defines a second receiving hole 21, two second shaft holes 23,two pivot holes 25, and four receiving holes 27. The second shaft holes23 and the pivot holes 25 are defined in a sidewall of the first swingmember 20. The second shaft holes 23, communicated with the secondreceiving hole 21, are aligned with the same axis, such as the Y axis inthe illustrated embodiment. The pivot holes 25 are aligned in the sameaxis and have an axis substantially perpendicular to that of the secondshaft holes 23. The receiving holes 27 are defined in a top of the firstswing member 20; and each receiving hole 27 communicates with one of thesecond shaft holes 23 and the pivot holes 25. The first swing member 20is rotatably received in the first receiving hole 11 around the firstpivots 30.

The first pivots 30 are cylindrical, each having two portions withdifferent diameters. Each first pivot 30 includes a latching portion 31and a rotating portion 33 smaller than the latching portion 31. Thelatching portion 31 is fixed in one of the first shaft holes 13. Inorder to prevent the first pivot 30 from rotating in the flange 10, therotation mechanism 100 further includes two first locking members 19.The first locking member 19 is received in the locking hole 17, andresisting the latching portion 31 of the first pivot 30. In theillustrated embodiment, the first locking member 19 is a socket screw.

The rotation mechanism 100 further includes two first tubes 40 fixed inthe second shaft holes 23 of the first swing member 20. The first tubes40 are rotatably sleeved on the rotating portions 33 of the first pivots30. In order to prevent the first tubes 40 from rotating relative to thefirst swing member 20, the rotation mechanism 100 further includes twosecond locking members 28. The second locking member 28 has a structuresimilar to the first locking member 19. The second locking member 28 isreceived in the receiving hole 27, and resisting the first tube 40. Inthe illustrated embodiment, the second locking member 28 is a socketscrew.

The second swing member 50 is substantially annular. The second swingmember 50 defines a circular third receiving hole 51 and two third shaftholes 53 having axes substantially perpendicular to that of the thirdreceiving hole 51. The third shaft holes 53, communicated with the thirdreceiving hole 51, are defined in a sidewall of the second swing member50 and are aligned with the same axis, such as the X axis in theillustrated embodiment. The second swing member 50 further defines a keyslot 511 in the sidewall and communicating with the third receiving hole51. The second swing member 50 is rotatable around the second pivots 60in the second receiving hole 21 of the first swing member 20.

The second pivots 60 have a structure similar to the first pivots 30.Each second pivot 60 includes a latching portion 61 and a rotatingportion 63 smaller than the latching portion 61. The latching portion 61is fixed in one of the pivot holes 25. In order to prevent the secondpivot 60 from rotating in the pivot hole 25 of the first swing member20, the rotation mechanism 100 further includes two third lockingmembers 29. The third locking member 29 has a structure similar to thefirst locking member 19. The third locking member 29 is received in thereceiving hole 27, and resisting the latching portion 61 of the secondpivot 60. In the illustrated embodiment, the third locking member 29 isa socket screw.

The rotation mechanism 100 further includes two second tubes 70 fixed inthe third shaft holes 53 of the second swing member 50. The second tubes70 have a structure similar to the first tubes 40. The second tubes 70are rotatably sleeved on the rotating portions 63 of the second pivots60.

The rotation mechanism 100 further includes a sleeve 80 fixed in thethird receiving hole 51 of the second swing member 50. The sleeve 80defines a positioning hole 81 and a key slot 83. The key slot 83 isdefined in an outer surface of the sleeve 80. The sleeve 80 furtherdefines a spline slot 811 along the axial direction of the positioninghole 81. The rotation mechanism 100 further includes a key 85 receivedin the key slot 511 of the second swing member 50 and the key slot 83 ofthe sleeve 80, thus preventing the sleeve 80 from rotating relative tothe second swing member 50.

The shaft 90 defines a spline slot 91 to engage with the spline slot 811of the sleeve 80, thus preventing the shaft 90 from rotating relative tothe sleeve 80. The shaft 90 is slidable along an axis of the sleeve 80.Thus, the shaft 90 is non-rotatably and slidably received in the secondswing member 50.

Referring to FIG. 4 and FIG. 5, during assembly of the rotationmechanism 100, the sleeve 80 is received in the third receiving hole 51of the second swing member 50 and fixed to the second swing member 50via the key 85. The second tubes 70 are received in and fixed in thethird shaft holes 53 of the second swing member 50. The second swingmember 50 is received in the second receiving hole 21 of the first swingmember 20. Each second pivot 60 runs through one second tube 70, onepivot hole 25 and is received in the third receiving hole 53. The thirdlocking members 29 are received in two opposite receiving holes 27, andresisting the second pivots 60. Thereby, the second swing member 50 ispivoted in the first swing member 20 via the second pivots 60. The firstswing member 20 is received in the first receiving hole 11. Each firstpivot 30 runs through one first tube 40, one first shaft hole 13 of theflange 10, and is received in the second receiving hole 21 of the firstswing member 20. The second locking members 28 are received in anothertwo opposite receiving holes 27, and resisting the first tube 40. Thefirst locking members 19 are received in the locking holes 17, andresisting the first pivots 30. Thereby, the first swing member 20 ispivoted in the flange 10 via the first pivots 30. The shaft 90 ispositioned in the positioning hole 81 of the sleeve 80, and the assemblyof the rotation mechanism 100 is complete.

When the rotation mechanism 100 is applied to the robot 200, the flange10 is fixed on the gear 202, and a bottom end of the shaft 90 is movablyconnected to the movable platform 203.

In operation, as shown in FIG. 1, in an original state of the robot 200,the movable platform 203 is directly under the base 201 and the shaft 90is substantially perpendicular to the flange 10. When the robot 200 isin operating mode, the control arms 205 are swung by the secondactuators 209 to move the movable platform 203 relative to the base 201,thus the shaft 90 is angled with respect to the flange 10. When theshaft 90 is angled with respect to the flange 10, the first swing member20 and the second swing member 50 are rotatable around the X axis and Yaxis, respectively, allowing the shaft 90 to swing relative to theflange 10. The shaft 90 is slidable in sleeve 80, allowing displacementof the movable platform 203 relative to the flange 10 for moving of themovable platform 203. The first actuator 207 rotates the gear 202 torotate the flange 10, thus the first swing member 20, the second swingmember 50, the sleeve 80, and the shaft 90 also rotate. As such, therotation of the first actuator 207 is transmitted to a tool (not shown)mounted on the movable platform 203.

The robot 200 has a wide range of movement and is more flexible sincethe shaft 90 is not only rotatable with respect to the flange 10, butthe shaft 90 also can swing on the X axis and Y axis, and slide alongthe sleeve 80. In addition, the shaft 90 and the sleeve 80 are generallyavailable off-the-shelf components, thus providing higherinterchangeability, longer service time, and higher precision.

Alternatively, the first, second, third locking members 19, 28, 29 andthe key 85 may be omitted. The first tubes 40 and the second tubes 70may be omitted. If the sleeve 80 is replaced by a linear bearing, thespline slot 91 may be omitted. The sleeve 80 may be omitted when thespline slot 811 is defined in the second swing member 50. The movementof the first actuator 207 may be transmitted to the flange 10 via otherstructures. The driving method for driving the flange 10 by the firstactuator 207 is not limited to gear transmission but also includes belttransmission.

Finally, while various embodiments have been described and illustrated,the disclosure is not to be construed as being limited thereto. Variousmodifications can be made to the embodiments by those skilled in the artwithout departing from the true spirit and scope of the disclosure asdefined by the appended claims.

1. A rotation mechanism for a robot, comprising: a flange; a shaftextending along a first axis; a first swing member rotatably connectedto and received in the flange around a second axis substantiallyperpendicular to the first axis; and a second swing member rotatablyconnected to and received in the first swing member around a third axissubstantially perpendicular to the first axis and the second axis;wherein the shaft extends through the flange, the first swing member,and the second swing member; and the shaft is non-rotatably and slidablyreceived in the second swing member.
 2. The rotation mechanism of claim1 further comprising two first pivots and two second pivots; wherein theflange defines two first shaft holes aligned with the second axis, thefirst swing member defines two second shaft holes aligned with thesecond axis, each first pivot is received in one first shaft hole andone second shaft hole to rotatably connect the shaft with the firstswing member; the first swing member defines two pivot holes alignedwith the third axis, the second swing member defines two third shaftholes aligned with the third axis, and each second pivot is received inone pivot hole and one third shaft hole to rotatably connect the secondswing member with the first swing member.
 3. The rotation mechanism ofclaim 2, wherein the flange defines a first receiving hole to receivethe first swing member, the first swing member defines a secondreceiving hole to receive the second swing member, and the second swingmember defines a third receiving hole to receive the shaft.
 4. Therotation mechanism of claim 2, wherein each of the first pivots and thesecond pivots comprises a latching portion and a rotating portionsmaller than the latching portion; the rotation mechanism furthercomprises two first tubes and two second tubes, the first tubesrotatably sleeved on the rotating portions of the first pivots and thesecond tubes rotatably sleeved on the rotating portions of the secondpivots.
 5. The rotation mechanism of claim 4, wherein the flange definestwo locking holes with axes parallel to the first axis, the first swingmember defines four receiving holes parallel to the first axis; therotation mechanism further comprises a plurality of locking members; twolocking members engage the locking holes and resist the latchingportions of the first pivots, two locking members engage two receivingholes and resist the first tubes, two locking members engage another tworeceiving holes and resist the latching portions of the second pivots.6. The rotation mechanism of claim 1 further comprising a sleeve fixedin the second swing member, the shaft being non-rotatably and slidablyreceived in the sleeve.